The Scientific Research of Barry Tomlinson
von Aderkas, Patrick .
Evolutionary history of pollination drops.
Pollination drops are ovular secretions that facilitate pollen delivery into gymnosperm ovules. Known from plants with the earliest types of seed habit, pollination drops capture pollen and deliver it through the opening in the ovule, the micropyle. The drop assists in germination. Barry Tomlinsonís pioneering work on active and passive methods of pollen capture by pollination drops contributed to a sea change in how we think about these drops. If drops of yews, junipers and podocarps, can respond to pollen by retracting into the ovule, then what is the mechanism? Using atomic spectroscopy to study calcium, HPLC to study sugars, and mass spectrometry to study proteins, a picture of a compound-rich soup has emerged. Pollination drops have an abundance of anti-microbial defense proteins, carbohydrate-modifying enzymes, not to mention calcium and carbohydrates. Some classes of compounds are shared with extra-floral nectaries and nectaries. It has even been recently argued that the nectar-like nature of pollination drops provides indirect evidence of nectar reward-driven insect pollination having evolved much earlier than previously thought. Molecular biological techniques (western blots, EM of gold-labeled antibodies to thaumatin-like proteins), have revealed that compounds are differentially produced from only the sporophytic portions of the ovule, which presumably is the site of the mechanism. We still have no idea of how active retraction functions, proving once again that Barry Tomlinson is ahead of his time.
The broader impact of this knowledge lies in understanding the evolution of pollination systems, which lie at the heart of agriculture and forestry.
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1 - University of Victoria, Biology, Victoria, B.C., Canada
Presentation Type: Symposium or Colloquium Presentation
Location: 552A/Convention Center
Date: Wednesday, August 4th, 2010
Time: 2:15 PM